Stimulus properties such as similarity-dissimilarity and novelty-familiarity are inherently relational and are embedded in most stimulus contexts. The specific aim of the present investigation is to analyze and enhance the relational characteristics of stimulus arrays in order to facilitate performance on tasks such as oddity and match-to-sample. Both mentally retarded and young nonretarded children are particularly prone to failure on these relational tasks (Greenfield, 1985; Soraci, Deckner, Haenlein, Baumeister, Murata-Soraci, & Blanton, 1987). Converging evidence from various studies suggests that a critical factor in the performance discrepancies between retarded and nonretarded children is a differential sensitivity to relational information (e.g., Soraci, Deckner, & Baumeister, 1989). In the proposed studies, emphasis is placed on facilitating the detection of relevant stimulus relations as a "front-end" (Brown, Collins, & Deguid, 1989) intervention strategy. The proposed studies are divided into four sections: I. Oddity, II. Induction of Other Relational Concepts, III. Learning to Exclude and Learning by Exclusion; and IV. Stimulus Equivalence.